Abstract: A wafer placement table includes a conductor unit. In the wafer placement table, a sub-RF electrode (first conductive layer) and a jumper layer (second conductive layer) are embedded at different levels in a ceramic substrate having a wafer placement surface, and the conductor unit establishes electrical continuity between the sub-RF electrode and the jumper layer. The conductor unit is a transversely placed coil or a transversely placed perforated cylindrical body.

Abstract: An AlN ceramic substrate of the present invention contains yttrium aluminate, and has a volume resistivity of 3×109 ?cm or more at 550° C.

Abstract: An AlN joined body includes a first AlN member and a second AlN member that are joined together. The content of yttria in the first AlN member is equal to or below the detection limit. The second AlN member contains yttria.

Abstract: A heater for a semiconductor manufacturing apparatus, the heater includes an AlN ceramic substrate and a heating element embedded inside the AlN ceramic substrate. The AlN ceramic substrate contains O, C, Ti, Ca, and Y as impurity elements, includes an yttrium aluminate phase as a crystal phase, and has a Ti/Ca mass ratio of 0.13 or more, and a TiN phase is not detected in an XRD profile measured with Cu K-? radiation.

Abstract: A heater for a semiconductor manufacturing apparatus, the heater includes an AlN ceramic substrate and a heating element embedded inside the AlN ceramic substrate. The AlN ceramic substrate contains O, C, Ti, Ca, and Y as impurity elements, includes an yttrium aluminate phase as a crystal phase, and has a Ti/Ca mass ratio of 0.13 or more, and a TiN phase is not detected in an XRD profile measured with Cu K-? radiation.

Abstract: A heater for a semiconductor manufacturing apparatus, the heater includes an AlN ceramic substrate and a heating element embedded inside the AlN ceramic substrate. The AlN ceramic substrate contains O, C, Ti, Ca, and Y as impurity elements, includes an yttrium aluminate phase as a crystal phase, and has a Ti/Ca mass ratio of 0.13 or more, and a TiN phase is not detected in an XRD profile measured with Cu K-? radiation.

Abstract: A heater for a semiconductor manufacturing apparatus, the heater includes an AlN ceramic substrate and a heating element embedded inside the AlN ceramic substrate. The AlN ceramic substrate contains O, C, Ti, Ca, and Y as impurity elements, includes an yttrium aluminate phase as a crystal phase, and has a Ti/Ca mass ratio of 0.13 or more, and a TiN phase is not detected in an XRD profile measured with Cu K-? radiation.

Abstract: A heater for a semiconductor manufacturing apparatus, the heater includes an AlN ceramic substrate and a heating element embedded inside the AlN ceramic substrate. The AlN ceramic substrate contains O, C, Ti, Ca, and Y as impurity elements, includes an yttrium aluminate phase as a crystal phase, and has a Ti/Ca mass ratio of 0.13 or more, and a TiN phase is not detected in an XRD profile measured with Cu K-? radiation.

Abstract: An iron alloy according to the present invention comprises: Al in an amount of from 3 to 5.5%; Mn in an amount from 0.2 to 6%; and the balance being iron (Fe), and inevitable impurities and/or a modifying element; when the entirety is taken as 100%. Since a high damping factor is obtainable at a low-strain amplitude, this iron alloy demonstrates a stable damping property even in a high-temperature region. Moreover, since the alloying elements are Al and Mn alone, and since their contents are less, the iron alloy according to the present invention is low in cost.

Abstract: An iron alloy according to the present invention comprises: Al in an amount of from 3 to 5.5%; Mn in an amount from 0.2 to 6%; and the balance being iron (Fe), and inevitable impurities and/or a modifying element; when the entirety is taken as 100%. Since a high damping factor is obtainable at a low-strain amplitude, this iron alloy demonstrates a stable damping property even in a high-temperature region. Moreover, since the alloying elements are Al and Mn alone, and since their contents are less, the iron alloy according to the present invention is low in cost.

Abstract: The present invention is such that it is an assignment to be solved to provide a process for producing aluminum composite material in which an iron sintered body of much higher adhesion is cast-in inserted with aluminum. A process according to the present invention for producing aluminum composite material is characterized in that it has: a preform molding step of molding a porous iron sintered-material preform by molding an iron powder so that an occupational volumetric fraction becomes from 50% or more to 70% or less, and then by sintering the iron powder, thereby molding a porous iron sintered material preform; and a composite-material forming step of placing said preform in a casting die whose die temperature is from 200° C. or more to 400° C. or less, the preform being preheated at a preheating temperature of from 300° C. or more to 400° C.